Obesity Flashcards
what is better at predicting cardio-respiratory comorbidities than BMI
waist or collar circumference
BMI limitations
- not a direct measure of adipose tissue or fat distribution
- inaccurate at height extremes of with lean body mass
ideal body weight
IBW (kg) = height in cm - x
x=100 for men, 105 for women
lean body weight
total body weight - adipose tissue
LBW=IBWx1.3
fat distribution patterns
apple/android: male, correlation with metabolic syndrome, increased morbidity and mortality
pear/gynoid: women, not correlated with metabolic syndrome
obesity BMI
> 30
morbidly obese BMI
> 40 or >35 with obesity-related comorbidity
obesity - cardiovascular changes
- increase in CO (SV), blood volume, arrhythmias, workload on heart which leads to hypertrophy, HTN (blood viscosity, catecholamine and estrogen release)
- hyperinsulinemia: increased levels of norepinephrine and angiotensinogen
total body water for obese patient
40%
obesity - coagulation changes
- hypercoagulability, increased risk of DVT, CVA
- adipose tissues promote chronic inflammatory state
- increased clotting factors
obesity - respiratory changes
- diaphragm cephalad
- decreased: chest wall compliance, lung compliance, FRC, ERV, VC, TLC
- increased: elastic resistance, work of breathing, pulmonary blood volume
- unchanged: residual volume and closing capacity, FEV/FVC
*maintain normocapnia by increasing MV with rapid, shallow breathing
obstructive sleep apnea diagnosis criteria and 3 types
->10 seconds, >15 episodes per hour, >4% saturation decrease
- OSA: respiratory efforts without airflow
- central sleep apnea: no respiratory efforts
- mixed
STOP BANG - OSA criteria
snoring tiredness observed stop breathing blood pressure BMI>35 age>50 neck circumference>40 cm gender=male
- high risk = more than 3
- majority of patients are undiagnosed so it is important to screen
Pickwickian syndrome
- obesity hypoventilation syndrome (OHS)
- long term result of OSA
- hypoventilation while awake with PaCO2>45 mmHg
obesity - gastric changes
- increased: gastric pressure, GERD, volume, acidity, gallstones, pancreatitis
- decreased: LES tone
- delayed gastric emptying
obesity - hepatic changes
- non-alcoholic fatty liver disease leads to cirrhosis: due to adipose tissue, impaired insulin activity, and inflammatory cytokines
- elevated ALT
obesity - endocrine changes
- decreased insulin secretion, increased resistance
- hypothyroidism: thyroid hormone resistance in peripheral tissues, increased stimulation hormone levels
metabolic syndrome
- abdominal obesity: waist >102 cm in men, >88 in women
- triglycerides: >150 mg/dL
- HDL: <40 mg/dL in men, <50 in women
- BP: >130/85
- fasting glucose: >110 mg/dL
*need 3/5
obesity - cancer changes
-3.2% of all new cancers are attributable to obesity
obesity pharmacology - lipophilic drugs
- increased volume of distribution, prolonged half life
- do not give much
obesity pharmacology - hydrophilic drugs
- volume of distribution unchanged
- dose for IBW
obesity pharmacology - dose non-depolarizing muscle relaxants on ____
IBW
obesity pharmacology - dose succinylcholine on ____
TBW - due to increased pseudocholinesterase activity
obesity pharmacology - dose Propofol induction on ____, maintenance on ____
LBW
TBW, and decrease with time to avoid accumulation
obesity pharmacology - dose opioids
initial doses are the same, repeat doses are less predictable
categories of bariatric surgery
- gastric restrictive
- restrictive and nutrient malabsorptive
s/s of anastomotic leak
- unexplained tachycardia
- fever
- abdominal pain
- shoulder pain
- SOB
- hypotension
- hiccups
- restlessness
Obesity Surgery-Mortality Risk Score
- BMI>50
- male
- HTN
- high risk DVT
- age>45
0-1: low
2-3: intermediate
4-5: high
obesity - estimated blood volume
45-55 mL/kg
